Constellation

How this effect works

Unlike a particle network, which connects everything to everything nearby, a constellation only exists where you are looking. Every frame we collect the stars inside the cursor's reach — a simple distance check — and only that handful is considered for lines. Two of them get connected when they are closer than the link distance, and the line fades with distance, so constellations assemble and dissolve as you sweep across the sky.

That "only near the cursor" rule is also the performance trick: comparing every star with every other star costs count², but comparing only the ~20 stars under your cursor costs almost nothing, which is why this effect can afford a dense sky. The light-up layer brightens and enlarges exactly the stars that are inside the reach, so the sky answers your hand; the field itself just drifts and twinkles — each star carries a phase offset into one shared sine wave.